Sometimes therapeutic substances, such as drugs, biologics, etc., are infused intraparenchymally or intracerebroventricularly to treat brain disorders, such as malignancies or neurodegenerative diseases. Co-assigned U.S. patent application Ser. No. 09/540,444, filed Mar. 31, 2000 (now U.S. Pat. No. 6,551,290), and U.S. patent application Ser. No. 09/625,751, filed Jul. 26, 2000, now U.S. Pat. No. 6,945,969, issued Sep. 20, 2005 (both incorporated herein by reference) disclose catheters that are particularly well suited for intraparenchymal or intraventricular convection-enhanced infusion of therapeutic substances. As used herein, “IPA” means intraparenchymal, “ICV” means intracerebroventricular, and “intraventricular” and “ventricles” refer to cerebroventricles.
Previously, intracranial catheters have been anchored to the periosteum, which is a fibrous membrane covering the surface of bone. The periosteum has not provided as much stability as desired, and movement of the catheter anchor may result in changes in the location of the catheter tip.